Click on the “Provisioning” menu entry on the left hand side of the page;

Next to the expired provisioning profile there should be a “Renew” button: press it. The status should change to “Pending” and after a while it will go to “Active”;

Download the renewed profile and add it to the Organizer in XCode by dragging the new file onto it;

Delete the expired profile from the Organizer (if you try to build the application now, you should get the error “Provisioning profile can’t be found”);

Double click on your project name in the Targets section of the Groups and Files panel on XCode (somehow it seems to be different from clicking on the name of the project and getting the Project Info!);

Select the Build tab and scroll down to the Code Signing section;

Click on the value for the entry under the Code Signing Identity and select the right profile.